This invention pertains to sewer inspection devices along with structure for flushing of sewers and methods of scanning sewers for leaks, whereby a conventional jet nozzle unit that is used for flushing a sewer can also be used to advance a camera along a sewer.
It is well known in the sewer cleaning and flushing art to direct a hydraulic jet nozzle unit into the sewer and deliver water under pressure to it through a hose, with rearwardly-directed jets of water causing advance of the jet nozzle unit and hose along the sewer. Rewinding of the hose causes retraction of the jet nozzle unit with the jets of water flushing material ahead thereof along the sewer as the jet nozzle unit retracts.
It is also known in the art to inspect sewers for leaks which is normally done after cleaning or flushing thereof. Such known systems include either a film camera or, more commonly, a TV camera which is moved along the sewer and which is connected to a receiver aboveground, whereby an observer may watch the receiver to see leaks as they are seen by the TV camera. In such systems, the camera may be moved between adjacent manholes by a cable structure, such as shown in Latall, U.S. Pat. No. 3,739,089, with the TV camera being mounted on a skid, such as shown in Latall, U.S. Pat. No. 3,715,484. It is also known in the art to have a camera unit mounted on a self-propelled carriage, having a motor, which is supplied by an electric line or battery-powered to propel the carriage and the camera along a pipe. The latter type of units are relatively expensive and may involve the use of electric lines which could be hazardous in a water environment. The camera units which are propelled by cable require an initial leading of the cable along the sewer to an adjacent manhole and thus complicate the use thereof.